Training Zone
How to Train and Race in the Heat and Humidity
Lyndsay Tessier of Toronto finished 9th in the women’s marathon at the 2019 World Championships, and Evan Dunfee of Vancouver won a bronze medal in the 50K race walk. How they performed so well in Doha’s extreme heat and humidity was no accident
Lyndsay Tessier knew the 2019 World Athletics Championships were going to be hot. But it wasn’t until she stepped off the plane in Doha, Qatar that she realized just how brutal the conditions would be.
The mercury had climbed to around 40 C and Tessier’s sunglasses fogged up as soon as she emerged from the plane. Simply being outside made her sweat. “I was really panicked,” Tessier recalls. “I just thought it would be impossible to run a marathon in that heat.” But Tessier raced the marathon and excelled, finishing ninth in an event that saw 28 of the 68 starters – more than 40 per cent of the field – drop out. She attributes her performance to her fitness and the work she and her support team did to prepare for the hot conditions, including joining Team Canada athletes at a hot training camp in Spain for the two weeks before the competition.
Athletics Canada lead physiologist Trent Stellingwerff, who attended the camp, says it takes 10 to 14 days for the body to fully acclimate to the heat – that’s why runners who train outdoors throughout the year may struggle in a race or training run when the temperature suddenly rises in the spring. But training in hot conditions starts to create physiological changes in the body in as little as a week. One of the earliest is that athletes’ blood volume increases, which in turn increases the amount of blood their hearts pump throughout their bodies. That means they have lower heartrates for given efforts. Their sweat rate increases, giving them more ability to cool themselves, and their sweat becomes more watery, meaning the body loses less salt.
Athletes’ core body temperatures also drop by about half a degree Celsius, which means they can exert themselves longer before hitting a critical threshold. “There are quite profound changes that happen quite quickly, and [heat acclimation] is the No. 1 way to handle racing in the heat,” Stellingwerff says. (If travelling to the race location in advance isn’t possible, sauna sessions can be a useful alternative.)
Before lining up on the start line, Tessier donned an ice vest and rubbed ice cubes over her body so she would start the race with as low a body temperature as possible. Moving around the course, she grabbed water from every aid station to drink and douse herself with. She anticipated sweating a lot in the heat, and had specifically practised drinking large volumes during workouts so she would be able to consume all the water she needed during the race without having stomach issues.
Tessier had done all her training runs at a pace of roughly 3:30 per kilometre, but her coach, Steve Boyd, advised her to run no faster than 3:45 during the marathon, because of the conditions. “That was a bit of a tough pill to swallow,” Tessier says. “The ego doesn’t want to run that.”
But Tessier set out at the back of the pack and executed her race plan perfectly, gradually passing runners who had started too fast and succumbed to the conditions. She crossed the finish line smiling.
Canadian race walker Evan Dunfee, who was racing the day after Tessier, said watching Tessier’s performance filled him with confidence. On the day of his race, Dunfee did a one-kilometre warmup on the hotel treadmill, had a cold shower and immersed himself in a cold bath for 10 minutes before heading to the start line. Like Tessier, Dunfee planned to go out conservatively, and said he was amazed when some of the favourites took off hard at the start. Dunfee hung back, sticking to his plan and making a point of grabbing water and ice towels from every aid station. He estimates he poured roughly 75 litres of water over himself throughout the 50k race. Though Dunfee raced slower than he had gone on training runs, he worked his way through the field and finished third.
“You saw all these guys who were physiologically way more talented than I am, but they just weren’t doing those little things – they weren’t pouring water on themselves, they weren’t carrying an ice towel, just these little things that make such a big difference,” Dunfee says.
In addition to water, Tessier and Dunfee both had prepared bottles of electrolyte drink that they grabbed while on the course.
Tessier’s cont ained Maurten, while Dunfee used PowerBar Isoactive ( plus Coke closer to the end of the race to guard against f lavour fatigue).
Tessier and Dunfee say the lessons they learned are applicable to all athletes. These include giving yourself time to adjust to the heat, starting the race with as low a body temperature as possible, drinking lots of water and electrolytes and pouring water over yourself during exertion. And, perhaps most importantly, don’t go into a race expecting to hit a personal best when the temperature is high.
“Adjust your pacing to the heat,” Tessier says. “You’re going to have to hang up your ego and race the conditions.”